Acquisitions, Goodwill and Other Intangible Assets (Goodwill) (Details) € in Millions, $ in Millions				3 Months Ended	6 Months Ended	9 Months Ended		12 Months Ended
		Mar. 21, 2014 USD ($)	Feb. 12, 2014 USD ($)	Dec. 31, 2014 EUR (€)	Jun. 30, 2015 EUR (€)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2015 EUR (€)	Sep. 30, 2015 USD ($)	Jan. 30, 2015 USD ($)	Jun. 20, 2014 EUR (€)	Jun. 20, 2014 USD ($)
Goodwill [Line Items]
Goodwill (Note 7)	[1]							$ 62,983		$ 61,660
Payments to Acquire Businesses, Net of Cash Acquired						$ 1,738	$ 2,090
Increase (Decrease) in Intangible Assets, Current						(212)		302
Intangible assets subject to amortization								13,725		13,513
Indefinite-lived intangible assets								130		105
Total	[1]							13,855		13,618
Dispositions, currency exchange and other						(2,090)
Goodwill, Acquired During Period						768
Goodwill, period increase (decrease)						$ (1,323)
Lower Limit
Goodwill [Line Items]
Discount Rate						10.00%
Upper Limit
Goodwill [Line Items]
Discount Rate						15.50%
Acquisition API Healthcare
Goodwill [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired			$ 340
Increase (Decrease) in Intangible Assets, Current								125
Goodwill, Acquired During Period								280
Acquisition Thermo Fisher
Goodwill [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired		$ 1,065
Increase (Decrease) in Intangible Assets, Current								320
Goodwill, Acquired During Period								700
Acquisition Alstom
Goodwill [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired | €					€ (300)
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed | €				€ 260
Estimated Purchase Price to Aquire Business, Net of Cash Acquired | €												€ 12,350
Estimated Cash from Acquisition													$ 3,400
Anticipated Third Party Investment In Joint Venture | €												€ 2,400
Business Acquisition Date of Acquisition Agreement Approved						Sep. 08, 2015
Acquisition agreement including sale of some assets after close | €									€ 120
Purchase Price Amendment | €									€ 45
Energy Management
Goodwill [Line Items]
Goodwill (Note 7)								$ 4,570		4,093
Dispositions, currency exchange and other						$ (477)
Goodwill, Acquired During Period						0
Reporting Unit Percentage Of Fair Value In Excess Of Carrying Amount								10.00%
GECC
Goodwill [Line Items]
Goodwill (Note 7)	[1]							$ 11,456		11,460
Payments to Acquire Businesses, Net of Cash Acquired						1,677	$ 0
Total	[1]							$ 875		$ 1,177
Goodwill, period increase (decrease)						$ 4
GECC | Acquisition Milestone
Goodwill [Line Items]
Goodwill (Note 7)											$ 730
Intangible assets subject to amortization											345
Estimated Purchase Price to Aquire Business, Net of Cash Acquired											$ 1,750

[1] Amounts may not add due to rounding.